Menu hover colour help

it depends where you have added/edited your posted style.

for instance, there is an existent style for .nav a:hover in grey.css (apart from many other styles for .nav a):

.nav li:hover, .nav li.sfHover,
.nav a:focus, .nav a:hover, .nav a:active {
	background:		red#F4F4F4;
	outline:		0;
}

styles that occur later, further down, in stylesheets will have priority.

This is my grey.css i still cant get it to work :

Oh sorry i have done it now, just forgot to empty the page cacher, thanks for the help!